| Message ID | 1434541495-14934-1-git-send-email-fdmanana@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Wed, Jun 17, 2015 at 12:44:55PM +0100, fdmanana@kernel.org wrote: > Currently there is not way for a user to know what is the minimum size a > device of a btrfs filesystem can be resized to. Sometimes the value of > total allocated space (sum of all allocated chunks/device extents), which > can be parsed from 'btrfs filesystem show' and 'btrfs filesystem usage', > works as the minimum size, but sometimes it does not, namely when device > extents have to relocated to holes (unallocated space) within the new > size of the device (the total allocated space sum). > > This change adds the ability to reliably compute such minimum value and > extents 'btrfs filesystem resize' with the following syntax to get such > value: The test fails after I do this before unmount: $SUDO_HELPER $TOP/btrfs balance start -mconvert=single -sconvert=single -f $TEST_MNT shrink_test Output: ############### root_helper ../btrfs filesystem resize get_min_size ../tests/mnt 6480199680 bytes (6.04GiB) min size = 6480199680 ############### root_helper ../btrfs filesystem resize 6480199680 ../tests/mnt ERROR: unable to resize '../tests/mnt' - No space left on device Resize '../tests/mnt' of '6480199680' Last successful resize before this was: Resize '../tests/mnt' of '7553941504' > btrfs filesystem resize [devid:]get_min_size I don't think this is the right interface, IMHO this fits into the inspect-internal group. The syntax for 'fi resize' is a bit cumbersome, I'd like to avoid complicating it further. But you can keep it as-is until the the bugs are fixed. > --- a/Makefile.in > +++ b/Makefile.in > @@ -46,7 +46,7 @@ libbtrfs_objects = send-stream.o send-utils.o rbtree.o btrfs-list.o crc32c.o \ > libbtrfs_headers = send-stream.h send-utils.h send.h rbtree.h btrfs-list.h \ > crc32c.h list.h kerncompat.h radix-tree.h extent-cache.h \ > extent_io.h ioctl.h ctree.h btrfsck.h version.h > -TESTS = fsck-tests.sh convert-tests.sh > +TESTS = fsck-tests.sh convert-tests.sh shrink-min-size-tests.sh > > prefix ?= @prefix@ > exec_prefix = @exec_prefix@ > @@ -161,6 +161,10 @@ $(BUILDDIRS): > @echo "Making all in $(patsubst build-%,%,$@)" > $(Q)$(MAKE) $(MAKEOPTS) -C $(patsubst build-%,%,$@) > > +test-shrink-min-size: btrfs mkfs.btrfs > + @echo " [TEST] shrink-min-size-tests.sh" > + $(Q)bash tests/shrink-min-size-tests.sh Please move the test under the test-misc, for now it's a catch-all category. General comments to the test script(s): * the tests are supposed to be run unprivileged as much as possible, so the SUDO_HELPER needs to be used explicitly * use the git binaries everywhere (diff below) > +shrink_test() > +{ > + min_size=$(btrfs filesystem resize get_min_size $TEST_MNT) sudo helper, use binary from git > + if [ $? != 0 ]; then > + _fail "Failed to get minimum size" > + fi > + min_size=$(echo $min_size | cut -d ' ' -f 1) > + echo "min size = ${min_size}" >> $RESULTS > + run_check btrfs filesystem resize $min_size $TEST_MNT sudo helper, use binary from git > +} > + > +run_check truncate -s 20G $IMAGE > +run_check $SUDO_HELPER $TOP/mkfs.btrfs -f $IMAGE sudo helper not necessary, it's a file-backed image > +run_check $SUDO_HELPER mount $IMAGE $TEST_MNT > + > +# Create 7 data block groups, each with a size of 1Gb. > +for ((i = 1; i <= 7; i++)); do > + run_check fallocate -l 1G $TEST_MNT/foo$i This failed as the mountpoint is created by root and I'm running the test under my user. A chown after mount fixed it. > +done [...] @@ -23,19 +23,23 @@ setup_root_helper shrink_test() { - min_size=$(btrfs filesystem resize get_min_size $TEST_MNT) + min_size=$(run_check_stdout $SUDO_HELPER $TOP/btrfs filesystem resize get_min_size $TEST_MNT) if [ $? != 0 ]; then _fail "Failed to get minimum size" fi min_size=$(echo $min_size | cut -d ' ' -f 1) echo "min size = ${min_size}" >> $RESULTS - run_check btrfs filesystem resize $min_size $TEST_MNT + run_check $SUDO_HELPER $TOP/btrfs filesystem resize $min_size $TEST_MNT } run_check truncate -s 20G $IMAGE -run_check $SUDO_HELPER $TOP/mkfs.btrfs -f $IMAGE +run_check $TOP/mkfs.btrfs -f $IMAGE run_check $SUDO_HELPER mount $IMAGE $TEST_MNT +user=$(id -un) +group=$(id -gn) +run_check $SUDO_HELPER chown $user:$group $TEST_MNT + # Create 7 data block groups, each with a size of 1Gb. for ((i = 1; i <= 7; i++)); do run_check fallocate -l 1G $TEST_MNT/foo$i @@ -43,7 +47,7 @@ done # Make sure they are persisted (all the chunk, device and block group items # added to the chunk/dev/extent trees). -run_check btrfs filesystem sync $TEST_MNT +run_check $TOP/btrfs filesystem sync $TEST_MNT # Now remove 3 of those 1G files. This will result in 3 block groups becoming # unused, which will be automatically deleted by the cleaner kthread, and this @@ -58,9 +62,9 @@ run_check rm -f $TEST_MNT/foo6 # groups - it could have been sleeping when they become unused. Then wait a bit # to allow the cleaner kthread to delete them and then finally ensure the # transaction started by the cleaner kthread is committed. -run_check btrfs filesystem sync $TEST_MNT +run_check $TOP/btrfs filesystem sync $TEST_MNT sleep 3 -run_check btrfs filesystem sync $TEST_MNT +run_check $TOP/btrfs filesystem sync $TEST_MNT # Now attempt to get the minimum size we can resize the filesystem to and verify # the resize operation succeeds. This size closely matches the sum of the size --- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jun 29, 2015 at 4:42 PM, David Sterba <dsterba@suse.cz> wrote: > On Wed, Jun 17, 2015 at 12:44:55PM +0100, fdmanana@kernel.org wrote: >> Currently there is not way for a user to know what is the minimum size a >> device of a btrfs filesystem can be resized to. Sometimes the value of >> total allocated space (sum of all allocated chunks/device extents), which >> can be parsed from 'btrfs filesystem show' and 'btrfs filesystem usage', >> works as the minimum size, but sometimes it does not, namely when device >> extents have to relocated to holes (unallocated space) within the new >> size of the device (the total allocated space sum). >> >> This change adds the ability to reliably compute such minimum value and >> extents 'btrfs filesystem resize' with the following syntax to get such >> value: > > The test fails after I do this before unmount: > > $SUDO_HELPER $TOP/btrfs balance start -mconvert=single -sconvert=single -f $TEST_MNT > shrink_test Where are you doing this exactly? Just tried the following: https://friendpaste.com/2U7C4gBBLBjo4e2v1ZnJP2 > > Output: > > ############### root_helper ../btrfs filesystem resize get_min_size ../tests/mnt > 6480199680 bytes (6.04GiB) > min size = 6480199680 > ############### root_helper ../btrfs filesystem resize 6480199680 ../tests/mnt > ERROR: unable to resize '../tests/mnt' - No space left on device > Resize '../tests/mnt' of '6480199680' > > Last successful resize before this was: > Resize '../tests/mnt' of '7553941504' And it didn't fail for me on a 4.1 kernel at least. It produced those 2 sizes as well, but it didn't fail for any of them. thanks > >> btrfs filesystem resize [devid:]get_min_size > > I don't think this is the right interface, IMHO this fits into the > inspect-internal group. The syntax for 'fi resize' is a bit cumbersome, I'd > like to avoid complicating it further. But you can keep it as-is until the the > bugs are fixed. > >> --- a/Makefile.in >> +++ b/Makefile.in >> @@ -46,7 +46,7 @@ libbtrfs_objects = send-stream.o send-utils.o rbtree.o btrfs-list.o crc32c.o \ >> libbtrfs_headers = send-stream.h send-utils.h send.h rbtree.h btrfs-list.h \ >> crc32c.h list.h kerncompat.h radix-tree.h extent-cache.h \ >> extent_io.h ioctl.h ctree.h btrfsck.h version.h >> -TESTS = fsck-tests.sh convert-tests.sh >> +TESTS = fsck-tests.sh convert-tests.sh shrink-min-size-tests.sh >> >> prefix ?= @prefix@ >> exec_prefix = @exec_prefix@ >> @@ -161,6 +161,10 @@ $(BUILDDIRS): >> @echo "Making all in $(patsubst build-%,%,$@)" >> $(Q)$(MAKE) $(MAKEOPTS) -C $(patsubst build-%,%,$@) >> >> +test-shrink-min-size: btrfs mkfs.btrfs >> + @echo " [TEST] shrink-min-size-tests.sh" >> + $(Q)bash tests/shrink-min-size-tests.sh > > Please move the test under the test-misc, for now it's a catch-all category. > > General comments to the test script(s): > * the tests are supposed to be run unprivileged as much as possible, so the > SUDO_HELPER needs to be used explicitly > * use the git binaries everywhere > > (diff below) > >> +shrink_test() >> +{ >> + min_size=$(btrfs filesystem resize get_min_size $TEST_MNT) > > sudo helper, use binary from git > >> + if [ $? != 0 ]; then >> + _fail "Failed to get minimum size" >> + fi >> + min_size=$(echo $min_size | cut -d ' ' -f 1) >> + echo "min size = ${min_size}" >> $RESULTS >> + run_check btrfs filesystem resize $min_size $TEST_MNT > > sudo helper, use binary from git > >> +} >> + >> +run_check truncate -s 20G $IMAGE >> +run_check $SUDO_HELPER $TOP/mkfs.btrfs -f $IMAGE > > sudo helper not necessary, it's a file-backed image > >> +run_check $SUDO_HELPER mount $IMAGE $TEST_MNT >> + >> +# Create 7 data block groups, each with a size of 1Gb. >> +for ((i = 1; i <= 7; i++)); do >> + run_check fallocate -l 1G $TEST_MNT/foo$i > > This failed as the mountpoint is created by root and I'm running the > test under my user. A chown after mount fixed it. > >> +done > [...] > > @@ -23,19 +23,23 @@ setup_root_helper > > shrink_test() > { > - min_size=$(btrfs filesystem resize get_min_size $TEST_MNT) > + min_size=$(run_check_stdout $SUDO_HELPER $TOP/btrfs filesystem resize get_min_size $TEST_MNT) > if [ $? != 0 ]; then > _fail "Failed to get minimum size" > fi > min_size=$(echo $min_size | cut -d ' ' -f 1) > echo "min size = ${min_size}" >> $RESULTS > - run_check btrfs filesystem resize $min_size $TEST_MNT > + run_check $SUDO_HELPER $TOP/btrfs filesystem resize $min_size $TEST_MNT > } > > run_check truncate -s 20G $IMAGE > -run_check $SUDO_HELPER $TOP/mkfs.btrfs -f $IMAGE > +run_check $TOP/mkfs.btrfs -f $IMAGE > run_check $SUDO_HELPER mount $IMAGE $TEST_MNT > > +user=$(id -un) > +group=$(id -gn) > +run_check $SUDO_HELPER chown $user:$group $TEST_MNT > + > # Create 7 data block groups, each with a size of 1Gb. > for ((i = 1; i <= 7; i++)); do > run_check fallocate -l 1G $TEST_MNT/foo$i > @@ -43,7 +47,7 @@ done > > # Make sure they are persisted (all the chunk, device and block group items > # added to the chunk/dev/extent trees). > -run_check btrfs filesystem sync $TEST_MNT > +run_check $TOP/btrfs filesystem sync $TEST_MNT > > # Now remove 3 of those 1G files. This will result in 3 block groups becoming > # unused, which will be automatically deleted by the cleaner kthread, and this > @@ -58,9 +62,9 @@ run_check rm -f $TEST_MNT/foo6 > # groups - it could have been sleeping when they become unused. Then wait a bit > # to allow the cleaner kthread to delete them and then finally ensure the > # transaction started by the cleaner kthread is committed. > -run_check btrfs filesystem sync $TEST_MNT > +run_check $TOP/btrfs filesystem sync $TEST_MNT > sleep 3 > -run_check btrfs filesystem sync $TEST_MNT > +run_check $TOP/btrfs filesystem sync $TEST_MNT > > # Now attempt to get the minimum size we can resize the filesystem to and verify > # the resize operation succeeds. This size closely matches the sum of the size > --- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jun 29, 2015 at 05:15:12PM +0100, Filipe Manana wrote: > On Mon, Jun 29, 2015 at 4:42 PM, David Sterba <dsterba@suse.cz> wrote: > > On Wed, Jun 17, 2015 at 12:44:55PM +0100, fdmanana@kernel.org wrote: > > The test fails after I do this before unmount: > > > > $SUDO_HELPER $TOP/btrfs balance start -mconvert=single -sconvert=single -f $TEST_MNT > > shrink_test > > Where are you doing this exactly? > > Just tried the following: https://friendpaste.com/2U7C4gBBLBjo4e2v1ZnJP2 Like in the the first part of the diff. > > Output: > > > > ############### root_helper ../btrfs filesystem resize get_min_size ../tests/mnt > > 6480199680 bytes (6.04GiB) > > min size = 6480199680 > > ############### root_helper ../btrfs filesystem resize 6480199680 ../tests/mnt > > ERROR: unable to resize '../tests/mnt' - No space left on device > > Resize '../tests/mnt' of '6480199680' > > > > Last successful resize before this was: > > Resize '../tests/mnt' of '7553941504' > > And it didn't fail for me on a 4.1 kernel at least. It produced those > 2 sizes as well, but it didn't fail for any of them. The test was run on 4.0.5, I'm building a clean 4.1 + integration to verify it there. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jun 30, 2015 at 4:14 PM, David Sterba <dsterba@suse.cz> wrote: > On Mon, Jun 29, 2015 at 05:15:12PM +0100, Filipe Manana wrote: >> On Mon, Jun 29, 2015 at 4:42 PM, David Sterba <dsterba@suse.cz> wrote: >> > On Wed, Jun 17, 2015 at 12:44:55PM +0100, fdmanana@kernel.org wrote: >> > The test fails after I do this before unmount: >> > >> > $SUDO_HELPER $TOP/btrfs balance start -mconvert=single -sconvert=single -f $TEST_MNT >> > shrink_test >> >> Where are you doing this exactly? >> >> Just tried the following: https://friendpaste.com/2U7C4gBBLBjo4e2v1ZnJP2 > > Like in the the first part of the diff. > >> > Output: >> > >> > ############### root_helper ../btrfs filesystem resize get_min_size ../tests/mnt >> > 6480199680 bytes (6.04GiB) >> > min size = 6480199680 >> > ############### root_helper ../btrfs filesystem resize 6480199680 ../tests/mnt >> > ERROR: unable to resize '../tests/mnt' - No space left on device >> > Resize '../tests/mnt' of '6480199680' >> > >> > Last successful resize before this was: >> > Resize '../tests/mnt' of '7553941504' >> >> And it didn't fail for me on a 4.1 kernel at least. It produced those >> 2 sizes as well, but it didn't fail for any of them. > > The test was run on 4.0.5, I'm building a clean 4.1 + integration to > verify it there. Nevermind, I managed to reproduce it but by placing the balance/convert before the loop that tests the shrinking. btrfs_can_relocate() returns 0, meaning relocation should succeed if no other allocations happen in parallel, which is the case here, but btrfs_relocate_block_group() fails with ENOSPC - one of this functions isn't working as it should, I'll check what's going on soon. thanks -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/btrfs-filesystem.asciidoc b/Documentation/btrfs-filesystem.asciidoc index f1c35b6..45f8cf7 100644 --- a/Documentation/btrfs-filesystem.asciidoc +++ b/Documentation/btrfs-filesystem.asciidoc @@ -88,7 +88,7 @@ If a newlabel optional argument is passed, the label is changed. NOTE: the maximum allowable length shall be less than 256 chars // Some wording are extracted by the resize2fs man page -*resize* [<devid>:][+/-]<size>[kKmMgGtTpPeE]|[<devid>:]max <path>:: +*resize* [<devid>:][+/-]<size>[kKmMgGtTpPeE]|[<devid>:]max|[<devid>:]get_min_size <path>:: Resize a mounted filesystem identified by directory <path>. A particular device can be resized by specifying a <devid>. + @@ -108,6 +108,8 @@ KiB, MiB, GiB, TiB, PiB, or EiB, respectively. Case does not matter. + If \'max' is passed, the filesystem will occupy all available space on the device devid. +If \'get_min_size' is passed, return the minimum size the device can be +shrunk to, without performing any resize operation. + The resize command does not manipulate the size of underlying partition. If you wish to enlarge/reduce a filesystem, you must make sure you diff --git a/Makefile.in b/Makefile.in index 860a390..202c51e 100644 --- a/Makefile.in +++ b/Makefile.in @@ -46,7 +46,7 @@ libbtrfs_objects = send-stream.o send-utils.o rbtree.o btrfs-list.o crc32c.o \ libbtrfs_headers = send-stream.h send-utils.h send.h rbtree.h btrfs-list.h \ crc32c.h list.h kerncompat.h radix-tree.h extent-cache.h \ extent_io.h ioctl.h ctree.h btrfsck.h version.h -TESTS = fsck-tests.sh convert-tests.sh +TESTS = fsck-tests.sh convert-tests.sh shrink-min-size-tests.sh prefix ?= @prefix@ exec_prefix = @exec_prefix@ @@ -161,6 +161,10 @@ $(BUILDDIRS): @echo "Making all in $(patsubst build-%,%,$@)" $(Q)$(MAKE) $(MAKEOPTS) -C $(patsubst build-%,%,$@) +test-shrink-min-size: btrfs mkfs.btrfs + @echo " [TEST] shrink-min-size-tests.sh" + $(Q)bash tests/shrink-min-size-tests.sh + test-convert: btrfs btrfs-convert @echo " [TEST] convert-tests.sh" $(Q)bash tests/convert-tests.sh @@ -169,7 +173,7 @@ test-fsck: btrfs btrfs-image btrfs-corrupt-block btrfs-debug-tree mkfs.btrfs @echo " [TEST] fsck-tests.sh" $(Q)bash tests/fsck-tests.sh -test: test-fsck test-convert +test: test-fsck test-convert test-shrink-min-size # # NOTE: For static compiles, you need to have all the required libs diff --git a/cmds-filesystem.c b/cmds-filesystem.c index b93bb33..13b5bc5 100644 --- a/cmds-filesystem.c +++ b/cmds-filesystem.c @@ -1220,14 +1220,228 @@ static int cmd_defrag(int argc, char **argv) } static const char * const cmd_resize_usage[] = { - "btrfs filesystem resize [devid:][+/-]<newsize>[kKmMgGtTpPeE]|[devid:]max <path>", + "btrfs filesystem resize [devid:][+/-]<newsize>[kKmMgGtTpPeE]|[devid:]max|[devid:]get_min_size <path>", "Resize a filesystem", "If 'max' is passed, the filesystem will occupy all available space", "on the device 'devid'.", + "If 'get_min_size' is passed, return the minimum size the device can", + "be shrunk to.", "[kK] means KiB, which denotes 1KiB = 1024B, 1MiB = 1024KiB, etc.", NULL }; +struct dev_extent_elem { + u64 start; + /* inclusive end */ + u64 end; + struct list_head list; +}; + +static int add_dev_extent(struct list_head *list, + const u64 start, const u64 end, + const int append) +{ + struct dev_extent_elem *e; + + e = malloc(sizeof(*e)); + if (!e) + return -ENOMEM; + + e->start = start; + e->end = end; + + if (append) + list_add_tail(&e->list, list); + else + list_add(&e->list, list); + + return 0; +} + +static void free_dev_extent_list(struct list_head *list) +{ + while (!list_empty(list)) { + struct dev_extent_elem *e; + + e = list_first_entry(list, struct dev_extent_elem, list); + list_del(&e->list); + free(e); + } +} + +static void adjust_dev_min_size(struct list_head *extents, + struct list_head *holes, + u64 *min_size) +{ + /* + * If relocation of the block group of a device extent must happen (see + * below) scratch space is used for the relocation. So track here the + * size of the largest device extent that has to be relocated. We track + * only the largest and not the sum of the sizes of all relocated block + * groups because after each block group is relocated the running + * transaction is committed so that pinned space is released. + */ + u64 scratch_space = 0; + + /* + * List of device extents is sorted by descending order of the extent's + * end offset. If some extent goes beyond the computed minimum size, + * which initially matches the sum of the lenghts of all extents, + * we need to check if the extent can be relocated to an hole in the + * device between [0, *min_size[ (which is what the resize ioctl does). + */ + while (!list_empty(extents)) { + struct dev_extent_elem *e; + struct dev_extent_elem *h; + int found = 0; + u64 extent_len; + u64 hole_len = 0; + + e = list_first_entry(extents, struct dev_extent_elem, list); + if (e->end <= *min_size) + break; + + /* + * Our extent goes beyond the computed *min_size. See if we can + * find a hole large enough to relocate it to. If not we must stop + * and set *min_size to the end of the extent. + */ + extent_len = e->end - e->start + 1; + list_for_each_entry(h, holes, list) { + hole_len = h->end - h->start + 1; + if (hole_len >= extent_len) { + found = 1; + break; + } + } + + if (!found) { + *min_size = e->end + 1; + break; + } + + if (hole_len > extent_len) { + h->start += extent_len; + } else { + list_del(&h->list); + free(h); + } + + list_del(&e->list); + free(e); + + if (extent_len > scratch_space) + scratch_space = extent_len; + } + + *min_size += scratch_space; +} + +static int get_min_size(int fd, DIR *dirstream, const char *amount) +{ + int ret = 1; + char *p = strstr(amount, ":"); + u64 devid = 1; + /* + * Device allocations starts at 1Mb or at the value passed through the + * mount option alloc_start if it's bigger than 1Mb. The alloc_start + * option is used for debugging and testing only, and recently the + * possibility of deprecating/removing it has been discussed, so we + * ignore it here. + */ + u64 min_size = 1 * 1024 * 1024ull; + struct btrfs_ioctl_search_args args; + struct btrfs_ioctl_search_key *sk = &args.key; + u64 last_pos = (u64)-1; + LIST_HEAD(extents); + LIST_HEAD(holes); + + if (p && sscanf(amount, "%llu:get_min_size", &devid) != 1) { + fprintf(stderr, "Invalid parameter: %s\n", amount); + goto out; + } + + memset(&args, 0, sizeof(args)); + sk->tree_id = BTRFS_DEV_TREE_OBJECTID; + sk->min_objectid = devid; + sk->max_objectid = devid; + sk->max_type = BTRFS_DEV_EXTENT_KEY; + sk->min_type = BTRFS_DEV_EXTENT_KEY; + sk->min_offset = 0; + sk->max_offset = (u64)-1; + sk->min_transid = 0; + sk->max_transid = (u64)-1; + sk->nr_items = 4096; + + while (1) { + int i; + struct btrfs_ioctl_search_header *sh; + unsigned long off = 0; + + ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args); + if (ret < 0) { + fprintf(stderr, + "Error invoking tree search ioctl: %s\n", + strerror(errno)); + ret = 1; + goto out; + } + + if (sk->nr_items == 0) + break; + + for (i = 0; i < sk->nr_items; i++) { + struct btrfs_dev_extent *extent; + u64 len; + + sh = (struct btrfs_ioctl_search_header *)(args.buf + + off); + off += sizeof(*sh); + extent = (struct btrfs_dev_extent *)(args.buf + off); + off += sh->len; + + sk->min_objectid = sh->objectid; + sk->min_type = sh->type; + sk->min_offset = sh->offset + 1; + + if (sh->objectid != devid || + sh->type != BTRFS_DEV_EXTENT_KEY) + continue; + + len = btrfs_stack_dev_extent_length(extent); + min_size += len; + ret = add_dev_extent(&extents, sh->offset, + sh->offset + len - 1, 0); + + if (!ret && last_pos != (u64)-1 && + last_pos != sh->offset) + ret = add_dev_extent(&holes, last_pos, + sh->offset - 1, 1); + if (ret) { + fprintf(stderr, "Error: %s\n", strerror(-ret)); + ret = 1; + goto out; + } + + last_pos = sh->offset + len; + } + + if (sk->min_type != BTRFS_DEV_EXTENT_KEY || + sk->min_objectid != devid) + break; + } + + adjust_dev_min_size(&extents, &holes, &min_size); + printf("%llu bytes (%s)\n", min_size, pretty_size(min_size)); + ret = 0; +out: + close_file_or_dir(fd, dirstream); + free_dev_extent_list(&extents); + free_dev_extent_list(&holes); + + return ret; +} + static int cmd_resize(int argc, char **argv) { struct btrfs_ioctl_vol_args args; @@ -1269,6 +1483,9 @@ static int cmd_resize(int argc, char **argv) return 1; } + if (strstr(amount, "get_min_size")) + return get_min_size(fd, dirstream, amount); + printf("Resize '%s' of '%s'\n", path, amount); strncpy_null(args.name, amount); res = ioctl(fd, BTRFS_IOC_RESIZE, &args); diff --git a/ctree.h b/ctree.h index f14a795..7d74d1a 100644 --- a/ctree.h +++ b/ctree.h @@ -1491,6 +1491,9 @@ BTRFS_SETGET_FUNCS(dev_extent_chunk_offset, struct btrfs_dev_extent, chunk_offset, 64); BTRFS_SETGET_FUNCS(dev_extent_length, struct btrfs_dev_extent, length, 64); +BTRFS_SETGET_STACK_FUNCS(stack_dev_extent_length, struct btrfs_dev_extent, + length, 64); + static inline u8 *btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev) { unsigned long ptr = offsetof(struct btrfs_dev_extent, chunk_tree_uuid); diff --git a/tests/shrink-min-size-tests.sh b/tests/shrink-min-size-tests.sh new file mode 100755 index 0000000..33938b7 --- /dev/null +++ b/tests/shrink-min-size-tests.sh @@ -0,0 +1,72 @@ +#!/bin/bash +# +# Test getting the minimum size a filesystem can be resized to and verify we +# are able to resize (shrink) it to that size. +# + +unset TOP +unset LANG +LANG=C +SCRIPT_DIR=$(dirname $(realpath $0)) +TOP=$(realpath $SCRIPT_DIR/../) +TEST_MNT=${TEST_MNT:-$TOP/tests/mnt} +RESULTS="$TOP/tests/shrink-min-size-tests-results.txt" +IMAGE="$TOP/tests/test.img" + +source $TOP/tests/common + +rm -f $RESULTS + +check_prereq mkfs.btrfs +setup_root_helper + + +shrink_test() +{ + min_size=$(btrfs filesystem resize get_min_size $TEST_MNT) + if [ $? != 0 ]; then + _fail "Failed to get minimum size" + fi + min_size=$(echo $min_size | cut -d ' ' -f 1) + echo "min size = ${min_size}" >> $RESULTS + run_check btrfs filesystem resize $min_size $TEST_MNT +} + +run_check truncate -s 20G $IMAGE +run_check $SUDO_HELPER $TOP/mkfs.btrfs -f $IMAGE +run_check $SUDO_HELPER mount $IMAGE $TEST_MNT + +# Create 7 data block groups, each with a size of 1Gb. +for ((i = 1; i <= 7; i++)); do + run_check fallocate -l 1G $TEST_MNT/foo$i +done + +# Make sure they are persisted (all the chunk, device and block group items +# added to the chunk/dev/extent trees). +run_check btrfs filesystem sync $TEST_MNT + +# Now remove 3 of those 1G files. This will result in 3 block groups becoming +# unused, which will be automatically deleted by the cleaner kthread, and this +# will result in 3 holes (unallocated space) in the device (each with a size +# of 1Gb). + +run_check rm -f $TEST_MNT/foo2 +run_check rm -f $TEST_MNT/foo4 +run_check rm -f $TEST_MNT/foo6 + +# Sync once to wake up the cleaner kthread which will delete the unused block +# groups - it could have been sleeping when they become unused. Then wait a bit +# to allow the cleaner kthread to delete them and then finally ensure the +# transaction started by the cleaner kthread is committed. +run_check btrfs filesystem sync $TEST_MNT +sleep 3 +run_check btrfs filesystem sync $TEST_MNT + +# Now attempt to get the minimum size we can resize the filesystem to and verify +# the resize operation succeeds. This size closely matches the sum of the size +# of all the allocated device extents. +for ((i = 1; i <= 3; i++)); do + shrink_test +done + +run_check $SUDO_HELPER umount $TEST_MNT